Remark 3 
To maintain small \(||\mathbf {q}^*||_2\) , although an outlier in \(\left\lbrace \mathbf {q}_m^*\right\rbrace _{m\in \mathbb {M}}\)  exists, we minimize the sum of the norm instead of the squared norm in (REF ), which additionally guarantees the robustness of the solution [1]}.

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